There is a widely known vehicular air conditioner which enhances the heat exchanging efficiency at the runtime of heating of the main heat exchanger by recovering the ventilation heat exhausted from the inside of the vehicle interior to the outside of the vehicle interior (for example, see Japanese Laid-Open Patent Publication No. 2011-51466, and the publication of Japanese Patent No. 5186422).
A vehicular air conditioner mentioned in Japanese Laid-Open Patent Publication No. 2011-51466 is configured such that in a main heat exchanger using a heat pump circuit, an auxiliary heat exchanging portion for recovering the exhausted heat is branched and connected to a downstream side of an expansion valve in a refrigerant passage in a heat pump circuit. The auxiliary heat exchanging portion is configured such that a heat exchanger for heat exchanging with the air passing through a heat exhausting passage is disposed in the ventilation heat exhausting passage which exhausts the air inside the vehicle interior to the outside of the vehicle interior. The heat generator of the auxiliary heat exchanging portion supplies a refrigerant absorbed the heat from the air passing through the heat exhausting passage to the upstream portion of an indoor heat exchanger in the refrigerant passage of the main heat exchanger. Accordingly, the refrigerant supplied to the indoor heat exchanger recovers the hot heat from the ventilation air, which improves the heating efficiency.
Moreover in a vehicular air conditioner mentioned in the publication of Japanese Patent No. 5186422, an auxiliary indoor heat exchanger of an exhaust heat recovering device is disposed with a main indoor heat exchanger in the air introducing duct of a main heat exchanger. The exhaust heat recovering device has a heat pump circuit in which a refrigerant circulates between the auxiliary indoor heat exchanger and the ventilation heat exchanger. The ventilation heat exchanger is disposed in a ventilation heat exhausting passage which exhausts the air from inside of the vehicle interior to the outside of the vehicle interior. The exhaust heat recovering device supplies a refrigerant absorbed by the ventilation heat exchanger to the auxiliary indoor heat exchanger in the air introducing duct, and heats an air passed through the air introducing duct by the auxiliary indoor heat exchanger. Accordingly, as for the vehicular air conditioner, the refrigerant supplied to the auxiliary indoor neat exchanger recovers the hot heat from the ventilation air, which improves the heating efficiency.